High Quality Content by WIKIPEDIA articles! As with other spreadsheets, Microsoft Excel works only to limited accuracy because it retains only a certain number of figures to describe numbers (it has limited precision). Excel nominally works with 8-byte numbers by default, a modified 1985 version of the IEEE 754 specification (Besides numbers, Excel uses a few other data types.) Although Excel can display 30 decimal points, its precision for a specified number is confined to 15 significant figures, and calculations may have an accuracy that is even less due to three issues: round off,truncation, and binary storage.